from django.db import models
from django.core.exceptions import PermissionDenied
from django.contrib.auth.models import User, AnonymousUser
from django.core.validators import RegexValidator
from gestioncof.models import CofProfile
from django.utils.six.moves import reduce
import datetime
import re

def choices_length(choices):
    return reduce(lambda m, choice: max(m, len(choice[0])), choices, 0)

def default_promo():
    now = datetime.date.today()
    return now.month <= 8 and now.year-1 or now.year

class Account(models.Model):
    cofprofile = models.OneToOneField(
        CofProfile, on_delete = models.PROTECT,
        related_name = "account_kfet")
    trigramme = models.CharField(
        unique     = True,
        max_length = 3,
        validators = [RegexValidator(regex='^[^a-z]{3}$')])
    balance = models.DecimalField(
        max_digits = 6, decimal_places = 2,
        default = 0)
    frozen = models.BooleanField(default = False)
    # Optional
    PROMO_CHOICES = [(r,r) for r in range(1980, datetime.date.today().year+1)]
    promo = models.IntegerField(
        choices = PROMO_CHOICES,
        blank = True, null = True, default = default_promo())
    nickname = models.CharField(
        max_length = 255,
        blank = True, default = "")
    password = models.CharField(
        max_length = 255,
        unique = True,
        blank = True, null = True, default = None)

    def __str__(self):
        return self.trigramme

    @staticmethod
    def is_validandfree(trigramme):
        data = { 'is_valid' : False, 'is_free' : False }
        pattern = re.compile("^[^a-z]{3}$")
        data['is_valid'] = pattern.match(trigramme) and True or False
        try:
            account = Account.objects.get(trigramme=trigramme)
        except Account.DoesNotExist:
            data['is_free'] = True
        return data

    def real_balance(self):
        if (hasattr(self, 'negative')):
            return self.balance + self.negative.balance_offset
        return self.balance

    def read(self, auth_user = AnonymousUser()):
        user = self.cofprofile.user

    # Surcharge Méthode save() avec gestions de User et CofProfile
    # Args:
    # - data : datas pour User et CofProfile
    # Action:
    # - Enregistre User, CofProfile à partir de "data"
    # - Enregistre Account
    def save(self, data = {}, *args, **kwargs):
        if self.pk:
            # Account update

            # Updating User with data
            user = self.cofprofile.user
            user.first_name = data.get("first_name", user.first_name)
            user.last_name  = data.get("last_name", user.last_name)
            user.email      = data.get("email", user.email)
            user.save()
            # Updating CofProfile with data
            cof = self.cofprofile
            cof.departement = data.get("departement", cof.departement)
            cof.save()
            # Nickname is not editable by the user
            """
            if not auth_user.has_perm('kfet.change_account'):
                account_old = Account.objects.get(pk=self.pk)
                self.nickname = account_old.nickname
            """
        else:
            # New account

            # Checking if user has already an account
            username = data.get("username")
            try:
                user = User.objects.get(username=username)
                if hasattr(user.profile, "account_kfet"):
                    trigramme = user.profile.account_kfet.trigramme
                    raise Account.UserHasAccount(trigramme)
            except User.DoesNotExist:
                pass

            # Creating or updating User instance
            (user, _) = User.objects.get_or_create(username=username)
            if "first_name" in data:
                user.first_name = data['first_name']
            if "last_name" in data:
                user.last_name = data['last_name']
            if "email" in data:
                user.email = data['email']
            user.save()
            # Creating or updating CofProfile instance
            (cof, _) = CofProfile.objects.get_or_create(user=user)
            if "login_clipper" in data:
                cof.login_clipper = data['login_clipper']
            if "departement" in data:
                cof.departement = data['departement']
            cof.save()
        self.cofprofile = cof
        super(Account, self).save(*args, **kwargs)

    # Surcharge de delete
    # Pas de suppression possible
    # Cas à régler plus tard
    def delete(self, *args, **kwargs):
        pass

    class UserHasAccount(Exception):
        def __init__(self, trigramme):
            self.trigramme = trigramme

class AccountNegative(models.Model):
    account = models.OneToOneField(
        Account, on_delete = models.PROTECT,
        related_name = "negative")
    start = models.DateTimeField(default = datetime.datetime.now)
    balance_offset = models.DecimalField(
        max_digits = 6, decimal_places = 2,
        default = 0)
    authorized_overdraft = models.DecimalField(
        max_digits = 6, decimal_places = 2,
        default = 0)
    comment = models.CharField(max_length = 255, blank = True)

class Checkout(models.Model):
    created_by = models.ForeignKey(
        Account, on_delete = models.PROTECT,
        related_name = "+")
    name = models.CharField(max_length = 45)
    valid_from = models.DateTimeField()
    valid_to   = models.DateTimeField()
    balance = models.DecimalField(max_digits = 6, decimal_places = 2)
    is_protected = models.BooleanField(default = False)

class CheckoutTransfer(models.Model):
    from_checkout = models.ForeignKey(
        Checkout, on_delete = models.PROTECT,
        related_name = "transfers_from")
    to_checkout = models.ForeignKey(
        Checkout, on_delete = models.PROTECT,
        related_name = "transfers_to")
    amount = models.DecimalField(
        max_digits = 6, decimal_places = 2)

class Statement(models.Model):
    by = models.ForeignKey(
        Account, on_delete = models.PROTECT,
        related_name = "+")
    checkout = models.ForeignKey(
        Checkout, on_delete = models.PROTECT,
        related_name = "statements")
    balance_old  = models.DecimalField(max_digits = 6, decimal_places = 2)
    balance_new  = models.DecimalField(max_digits = 6, decimal_places = 2)
    amount_taken = models.DecimalField(max_digits = 6, decimal_places = 2)
    amount_error = models.DecimalField(max_digits = 6, decimal_places = 2)
    at = models.DateTimeField(auto_now_add = True)

class ArticleCategory(models.Model):
    name = models.CharField(max_length = 45)

class Article(models.Model):
    name    = models.CharField(max_length = 45)
    is_sold = models.BooleanField(default = True)
    price = models.DecimalField(max_digits = 6, decimal_places = 2)
    stock = models.IntegerField(default = 0)
    category = models.ForeignKey(
        ArticleCategory, on_delete = models.PROTECT,
        related_name = "articles")

class ArticleRule(models.Model):
    article_on = models.OneToOneField(
        Article, on_delete = models.PROTECT,
        related_name = "rule_on")
    article_to = models.OneToOneField(
        Article, on_delete = models.PROTECT,
        related_name = "rule_to")
    ratio = models.PositiveSmallIntegerField()

class Inventory(models.Model):
    articles = models.ManyToManyField(
        Article,
        through      = 'InventoryArticle',
        related_name = "inventories")
    by = models.ForeignKey(
        Account, on_delete = models.PROTECT,
        related_name = "+")
    at = models.DateTimeField(auto_now_add = True)
    # Optional
    order = models.OneToOneField(
        'Order', on_delete = models.PROTECT,
        related_name = "inventory",
        blank = True, null = True, default = None)

class InventoryArticle(models.Model):
    inventory = models.ForeignKey(
        Inventory, on_delete = models.PROTECT)
    article = models.ForeignKey(
        Article, on_delete = models.PROTECT)
    stock_old   = models.IntegerField()
    stock_new   = models.IntegerField()
    stock_error = models.IntegerField(default = 0)

class Supplier(models.Model):
    articles = models.ManyToManyField(
        Article,
        through      = 'SupplierArticle',
        related_name = "suppliers")
    name = models.CharField(max_length = 45)
    address = models.TextField()
    email = models.EmailField()
    phone = models.CharField(max_length = 10)
    comment = models.TextField()

class SupplierArticle(models.Model):
    supplier = models.ForeignKey(
        Supplier, on_delete = models.PROTECT)
    article = models.ForeignKey(
        Article, on_delete = models.PROTECT)
    BOX_TYPE_CHOICES = (
        ("caisse", "Caisse"),
        ("carton", "Carton"),
        ("palette", "Palette"),
        ("fût", "Fût"),
    )
    box_type = models.CharField(
        choices    = BOX_TYPE_CHOICES,
        max_length = choices_length(BOX_TYPE_CHOICES))
    box_capacity = models.PositiveSmallIntegerField()
    price_HT = models.DecimalField(max_digits = 7, decimal_places = 4)
    TVA      = models.DecimalField(max_digits = 4, decimal_places = 2)
    rights   = models.DecimalField(max_digits = 7, decimal_places = 4)

class Order(models.Model):
    supplier = models.ForeignKey(
        Supplier, on_delete = models.PROTECT,
        related_name = "orders")
    articles = models.ManyToManyField(
        Article,
        through        = "OrderArticle",
        related_name   = "orders")
    at = models.DateTimeField(auto_now_add = True)
    amount = models.DecimalField(max_digits = 6, decimal_places = 2)

class OrderArticle(models.Model):
    order = models.ForeignKey(
        Order, on_delete = models.PROTECT)
    article = models.ForeignKey(
        Article, on_delete = models.PROTECT)
    quantity_ordered = models.IntegerField()
    quantity_received = models.IntegerField()

class TransferGroup(models.Model):
    at = models.DateTimeField(auto_now_add = True)
    # Optional
    comment = models.CharField(
        max_length = 255,
        blank = True, default = "")
    valid_by = models.ForeignKey(
        Account, on_delete = models.PROTECT,
        related_name = "+",
        blank = True, null = True, default = None)

class Transfer(models.Model):
    group = models.ForeignKey(
        TransferGroup, on_delete = models.PROTECT,
        related_name = "transfers")
    from_acc = models.ForeignKey(
        Account, on_delete = models.PROTECT,
        related_name = "transfers_from")
    to_acc = models.ForeignKey(
        Account, on_delete = models.PROTECT,
        related_name = "transfers_to")
    amount = models.DecimalField(max_digits = 6, decimal_places = 2)
    # Optional
    canceled_by = models.ForeignKey(
        Account, on_delete = models.PROTECT,
        null = True, blank = True, default = None,
        related_name = "+")
    canceled_at = models.DateTimeField(
        null = True, blank = True, default = None)

class OperationGroup(models.Model):
    on_acc = models.ForeignKey(
        Account, on_delete = models.PROTECT,
        related_name = "operations")
    checkout = models.ForeignKey(
        Checkout, on_delete = models.PROTECT,
        related_name = "operations")
    at = models.DateTimeField(auto_now_add = True)
    amount = models.IntegerField()
    is_cof = models.BooleanField(default = False)
    # Optional
    comment = models.CharField(
        max_length = 255,
        blank = True, default = "")
    valid_by = models.ForeignKey(
        Account, on_delete = models.PROTECT,
        related_name = "+",
        blank = True, null = True, default = True)

class Operation(models.Model):
    PURCHASE = 'purchase'
    DEPOSIT  = 'deposit'
    WITHDRAW = 'withdraw'

    TYPE_ORDER_CHOICES = (
        (PURCHASE, 'Achat'),
        (DEPOSIT, 'Charge'),
        (WITHDRAW, 'Retrait'),
    )

    group = models.ForeignKey(
        OperationGroup, on_delete = models.PROTECT,
        related_name = "+")
    type = models.CharField(
        choices = TYPE_ORDER_CHOICES,
        max_length = choices_length(TYPE_ORDER_CHOICES))
    amount = models.DecimalField(max_digits = 6, decimal_places = 2)
    on_checkout = models.BooleanField(default = True)
    # Optional
    article = models.ForeignKey(
        Article, on_delete = models.PROTECT,
        related_name = "operations",
        blank = True, null = True, default = None)
    canceled_by = models.ForeignKey(
        Account, on_delete = models.PROTECT,
        related_name = "+",
        blank = True, null = True, default = None)
    canceled_at = models.DateTimeField(
        blank = True, null = True, default = None)
    addcost_for = models.ForeignKey(
        Account, on_delete = models.PROTECT,
        related_name = "addcosts",
        blank = True, null = True, default = None)
    addcost_amount = models.DecimalField(max_digits = 6, decimal_places = 2)

class GlobalPermissions(models.Model):
    class Meta:
        managed = False
        permissions = (
            ('is_team', 'Is part of the team'),
        )